The present invention relates to a pivoting door-type thrust reverser for an aircraft turbojet engine, more particularly one in which the rear portion of the thrust reverser door forms a boundary of a passage enabling a portion of the gases in a gas flow duct to bypass the rear portion of the thrust reverser door and to be redirected obliquely relative to the gas flow duct so as to prevent the bypass gas flow from generating forward thrust when the pivoting door is in its reverse thrust position.
Pivoting door-type thrust reversers for aircraft turbojet engines are well-known in the and typically comprise a thrust reverser door pivotally attached an engine cowling wherein an inner surface of the cowling forms an outer boundary of a gas flow duct. The thrust reverser door is pivotable between a forward thrust position, in which an inner surface of the thrust reverser door forms a portion of the outer boundary of the gas flow duct, and a reverse thrust position in which a front portion of the door moves outwardly from the cowling and a rear portion of the door moves inwardly into the gas flow duct so as to redirect the gases flowing in the gas flow duct outwardly through an opening in the cowling. An inner boundary of the gas flow duct may be formed by a casing enclosing the turbojet engine if the thrust reverser is utilized in a turbofan-type jet engine. In such turbofan-type jet engines, the gas flow duct may contain gas flow including the hot exhaust from the jet engine, as well as the cooler air from the turbofan, or the duct may direct the flow only of air from the turbofan.
The cowling typically has an aerodynamic outer surface, especially in cases in which the turbojet engine is suspended externally from the aircraft, to provide a low drag, aerodynamic airflow around the cowling.
FIG. 1 illustrates a typical thrust reverser for a cowling 1. The thrust reverser door 2 is pivotally attached to the cowling 1 so as to pivot about generally transverse axis 20 between the forward thrust position, illustrated in FIG. 1, and a reverse thrust position (not shown). The cowling has a rear portion 3 that is fixed to the remainder of the cowling by cowling portions extending between circumferentially spaced apart thrust reverser doors. A plurality of thrust reverser doors may be utilized, with the doors being circumferentially spaced apart around the circumference of the cowling 1. Each door may comprise outer panel 4 and inner panel 5. In the forward thrust position, the outer panel 4 is substantially flush with the outer surfaces of the cowling 1 and the rear portion 3 to provide aerodynamic air flow over the cowling structure. When in this position, the inner panel 5 forms a portion of the outer boundary of the gas flow duct 15.
The door 2 is moved between its forward and reverse thrust positions by an actuator 8 connected to a front structure of the cowling 1 and having an extendible and retractable rod attached to the door 2. As is well known in the art, extension and retraction of the rod will cause the door to move between the forward and reverse thrust positions.
When the thrust reverser is in the forward thrust mode, gases pass through the generally annular duct 15 in the direction of arrow 6. When the door is in the reverse thrust position, an opening in the cowling 1 is uncovered and the gases are redirected laterally outwardly through this opening. In the known pivoting door-type thrust reversers, the rear portion of the door 2 which pivots inwardly into the gas flow duct 15 provides substantially total obstruction of the gas flow duct 15. In some instances it is desirable to achieve such maximum obstruction of the gas flow duct during thrust reversal, but in other instances, depending upon the particular geometric and aerodynamic parameters, such maximum obstruction may constitute a drawback. During thrust reversal, it is important that gas flow through the openings in the cowling be of sufficient capacity to prevent stalling of the turbojet engine compressor, or otherwise affecting the operation of the compressor.
Typical pivoting door-type thrust reversers are shown in French Patents 1,482,538 and 2,030,304 and in U.S. Pat. No. 3,605,411.